The present invention relates to a muscle hardness meter which measures the hardness of muscle tissue of a living organism.
Heretofore, a range of muscle hardness meters have been used that measure the hardness of muscle tissue by applying pressure to a living organism.
These muscle hardness meters are provided with a primary pin that touches the living organism, and a secondary cylinder that encloses the primary pin (for example, refer to Patent document 1). The secondary cylinder is provided such that it can move forward or draw back with respect to the primary pin, and is continuously urged towards its distal side by a coiled spring. Furthermore, a switch is provided at a predetermined location at the rear of the secondary cylinder.
In such a construction, tension is applied to a section to be measured by pressing the front face of the secondary cylinder against the periphery of the section to be measured. In this state, the primary pin is pushed into the section to be measured. At this time, the secondary cylinder is installed such that it can move forward or draw back. Accordingly, the secondary cylinder sustains the pressure (reactive force) from the periphery of the section to be measured. As a result, the secondary cylinder resists the force exerted by the coiled spring, and regresses with respect to the primary pin. Then, the switch at its rear is turned on by the secondary cylinder at a certain timing, and a trigger signal is output from the switch. At this timing, the pressure (reactive force) that the primary pin sustains from the section to be measured is measured, so that the hardness of the muscle tissue of the living organism is measured.
[Patent document 1] Japanese Unexamined Patent Application, First Publication No. 10 H10-179524
However, in the muscle hardness meter as described above, the pressure value that the secondary cylinder sustains is set in advance according to the mechanical structure of the amount of shift (amount of regress) of the secondary cylinder and the spring constant of the coiled spring. Therefore, the dispersion of the pressure value set becomes large. As a result, there is a problem in that the hardness of muscle tissue cannot be measured accurately.
Furthermore, there is a case in which the pressures that the secondary cylinder and the primary pin sustain change rapidly due to the amount of force in the vicinity of the switch. In this case, the trigger signal cannot be output at appropriate timing. Therefore, there is a problem in that measurement cannot be performed with high accuracy.
Therefore, it is desirable to provide a muscle hardness meter that can make measurements easily with high accuracy using a simple construction.